The present invention relates generally to sensors including an alarm for sensing the level of pulverant material relative to the level of a liquid within the same container. The invention has particular utility with respect to sensing the level of salt within a salt-brine tank of a household water softener.
Household water softeners generally include a vessel containing an ion exchange resin intended to remove calcium and other minerals from a supply of water used within the household. From time to time, generally once every day or two, it becomes necessary to recharge the ion exchange resin so it can continue to perform its intended function. The recharging is accomplished by introducing a brine solution into the resin deck whereby a reverse ion exchange takes place freeing the calcium and other undesired ions which can then be flushed from the system and down the drain. Once the system is recharged, an amount of water is introduced into a tank containing block or particulate salt to form a new supply of brine for the next recharge cycle.
On introduction of the fresh water into contact with the salt, a portion of the salt dissolves in the water thereby lowering the level of the salt within the salt-brine tank. After a number of recharged cycles, it becomes necessary to add salt to the salt-brine tank. Since the recharging generally occurs automatically, little thought is given to the operation of the water softener system. Often, one senses that a water softener is out of salt only when one senses that the water no longer is as soft as desired and discovers that the salt-brine tank is out of salt and contains only a desired level of water. It is therefore an object of the present invention to alert a householder when the level of salt within the salt-brine tank has fallen below a desired minimum level and in particular below the maximum water level within the tank.
On rare occasions, a water softener ceases to operate in the intended fashion and, rather than introducing a desired or measured supply of water into the salt-brine tank following a recharging of the ion resin bed, the system continues to introduce an excessive amount of water to the point that the salt-brine tank may even overflow which can cause significant damage to surrounding equipment, household furnishings, and the like. It is therefore an object of the present invention to provide an alarm which will alert the householder in the event that an excessive amount of water is introduced into the salt-brine tank.